Terms of use

The calculators are free to use. Please read the limits below before you base a business decision on them.

PaywallLab is run by Gonçalo Raposeiro, Lisbon, Portugal. Last updated 2026-10-06.

Using the calculators

You can use the calculators for any personal or commercial purpose. The results are statistical estimates based on the numbers you enter and the assumptions described on our methodology page. They are not financial, legal or tax advice.

No warranty

We work hard to keep the math right and test it against reference values, but the calculators are provided as they are, without any warranty. To the extent the law allows, we're not liable for losses that come from decisions made using them.

Paid plans

We'll publish separate terms for paid plans, including pricing and refunds, before we sell anything.

Contact

Questions about these terms: bgraposeiro@gmail.com. These terms are governed by Portuguese law.